Corp mdt overshoots assigned altitude in descent.

Attributes
ACN	143648
Time
Date	199004
Day	Fri
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : bgm
State Reference	NY
Altitude	msl bound lower : 21200 msl bound upper : 22000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zny tracon : psc
Operator	general aviation : corporate
Make Model Name	Medium Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other
Flight Phase	descent other
Route In Use	enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	Other
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 75 flight time total : 5100 flight time type : 1800
ASRS Report	143648
Person 2
Affiliation	Other
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	altitude deviation : overshoot non adherence : clearance
Independent Detector	other flight crewa
Resolutory Action	flight crew : returned to intended course or assigned course
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

End of a very long day. Autoplt inoperative. PF was hand flying aircraft. We were cleared to FL220 in the descent. We were also being radar vectored. I was putting the next leg's flight plan in the captain's VLF. At this time we were given direct to the bgm VOR. The captain looked down to put it in his VLF which I was using and we both heard the altitude alerter go off as we went 300' below our assigned altitude. By the time we recovered I saw 21,200' in the altimeter -- a deviation of 800'. The controller said nothing about the deviation. I definitely believe there are a number of contributing factors. No one was flying the aircraft as both pilots had heads down with the navigation equipment. Also contributory was fatigue due to a 13 hour duty day with a long over water flight.

Original NASA ASRS Text

Title: CORP MDT OVERSHOOTS ASSIGNED ALT IN DESCENT.

Narrative: END OF A VERY LONG DAY. AUTOPLT INOPERATIVE. PF WAS HAND FLYING ACFT. WE WERE CLRED TO FL220 IN THE DSNT. WE WERE ALSO BEING RADAR VECTORED. I WAS PUTTING THE NEXT LEG'S FLT PLAN IN THE CAPT'S VLF. AT THIS TIME WE WERE GIVEN DIRECT TO THE BGM VOR. THE CAPT LOOKED DOWN TO PUT IT IN HIS VLF WHICH I WAS USING AND WE BOTH HEARD THE ALT ALERTER GO OFF AS WE WENT 300' BELOW OUR ASSIGNED ALT. BY THE TIME WE RECOVERED I SAW 21,200' IN THE ALTIMETER -- A DEVIATION OF 800'. THE CTLR SAID NOTHING ABOUT THE DEVIATION. I DEFINITELY BELIEVE THERE ARE A NUMBER OF CONTRIBUTING FACTORS. NO ONE WAS FLYING THE ACFT AS BOTH PLTS HAD HEADS DOWN WITH THE NAVIGATION EQUIPMENT. ALSO CONTRIBUTORY WAS FATIGUE DUE TO A 13 HR DUTY DAY WITH A LONG OVER WATER FLT.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.